Process of making reproductions



Patented Aug. 18, 1925.

EMANUEL FABIAN, OF BERLIN-GHAELOTTENBUEG, GERMANY, ASSIGNGR TO HER- MANN I-IURWITZ & 00., A FIRM, 0F BERLIN, GERMANY.

PROCESS OF BIAKING REPRODUCTIONS.

No Drawing.

T 0 all whom it may concern.

Be it known that I, EMANUEL FABIAN, a citizen of Switzerland, residing at Berlin- Charlottenburg, in the State of Prussia, Germany, have invented certain new and useful Improvements in Processes of Mal:- ing Reproductions; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in the process of making reproductions of original records such as documents, and more particularly in the process described in my application for patent Ser. No. 581,541?) filed August 12, 1922, in which a solid plate is provided with an extremely thin coating of a liquid having an acid reaction which is an acidulated solution of a salt of a metal of which the hydroxide is insoluble, which layer is adapted to be acted upon by original records written in ammoniacal ink so that the portions of the plate coresponding to the lines of the record are capable of retaining a fatty ink (printers ink), While the latter is repelled by the portion of the plate corresponding to blank portions of the record. Thus a negative is obtained from which a practically unlimited number of copies can be printed.

In the process described in the said prior application the first preparation of the plate contains aluminum sulfate or other sulfates, and I have now found that this preparation is excellent when used in connection with original records made by means of ammoniacal inks. However, when used in connection with inks containing fixed alkalies, and more particularly the carbonates thereo'gf such as soda and potash, the result is less satisfactory. Though copies can be made from the negatives produced by such original records, yet a comparatively long con tact is necessary, so that in some cases certain components of the paper (particularly when using papers containing much loading or sizing material) may enter into reaction with the preparation, whereby blank portions of the plate may take up a small amount of the fatty inks. Further, the lines of the copies are not distinct and sharp.

N ow, it is desirable to use an ink containing fixed caustic alkalies or the carbonates thereof in lieu of the ammonia, because the Application filed September 10, 1924. $er1'al No. 737,004.

ammonia of the ink applied to the original document is vaporized with considerable rapidity, so that after some time the original record cannot be used for making new printing plates (negatives). Further it is open to the objection that the ammonia sometimes vaporizes from the ink, if the bottle containing the same is not closed up absolutely tight. Since fixed alkalies or the carbonates thereof do not vaporize, the inks containing fixed alkalies or the carbonates thereof will not be open to the above noted objection.

The object of the present improvements is to provide aprocess by virtue of which inks containing fixed alkalies or the carbonates thereof can be used, and in which after short contact a sharp and distinct negative copy is obtained, which will in turn give good printed copies, and with this object in view I produce a preparation on the plate in which the proportion of the sulfates or sulfuric acid, as compared to the other components, is materially reduced, or in which the said sulfates or sulfuric acid are entirely omitted. I have found that when using chloride or nitrates and the corresponding acids, the sensitiveness of the preparation is such that even a short contact with the original made by means of fixed alkalies or the carbonates thereof, is sufiicient to produce sharp and distinct lines on the plate, and that the blank portion of the plate does not ake up any particles of the ink. The sensitiveness is such that even neutral portions of the image react with the preparation of the plate. An important feature of my improved process consists in that the original record can be printed by means of ribbons impregnated with ink containing fixed alkalies or the carbonates thereof, and which in this respect are durable. The small amounts of the alkali transmitted from the ribbon to the paper are sufficient for producing good latent copies when bringing the same in contact with the plate prepared in the manner described.

EwampZe.A preparation suitable in my improved process contains in 100 parts by weight, 5 parts of nitrate of aluminum, 2 parts of alum, 7 parts of chlorid of magnesium, 7 parts of chlorid of iron, 10 parts of nitric acid, (25%) and 18 parts of glycerine.

As has been stated above the sulfates and the sulfuric acids can be entirely omitted. But I have found that in this case the lines of the original record adhere to the plate so strongly that they cannot be washed off with water after being used, and that it is neces sary to remove them by means of diluted acid, which is inconvenient because another liquid must be supplied to the operator. For this reason I prefer to add a small amount of sulfates or sulfuric acid to the preparation liquid, as has been stated in the above example. The action of the hydrochlorid acid and the nitric acid or the salts thereof cited in the above example is also performed by the strong organic acids such as formic acid, acetic acid, sulfocyanic acid and the salts thereof. Among other acids which might be of practical value in the process, phosphoric acid acts similarly to sulfuric acid.

The term fixed alkali as used in the appended claims, is intended to include caustic alkalies as Well as carbonated alkalies,

but this term does not include ammonia, which is often described as volatile alkali.

I claim l. The herein described process of producing a printing surface, which consists in treating a suitable foundation plate with an acid solution of a metal salt in which the sulfuric acid radical is not present in so large an amount as the radicals of other strong acids.

2. The herein described process of producing a printing surface, which consists in treating a suitable foundation plate With an acid solution of a metal salt in which solution the sulfuric acid radical is not present in nearly so large an amount, as the radicals of other strong acids, and placing thereon an original Written in ink containing fixed alkali.

In testimony whereof I hereunto affix my signature.

EMANUEL FABIAN. 

